Challenges for Intermountain West Native Wildflower Seed Production: Stand Establishment

Reliable commercial seed production of native plants is needed to restore rangelands of the Intermountain West. Direct seeding of native range plants has been generally problematic, especially for certain species. Fall planting is important, because seed of many species requires a period of cold to break dormancy (vernalization). Loss of soil moisture, soil crusting, bird damage, and other factors hinder emergence of fall planted seed. In previous research, the complexity of testing single factors has impeded succesful stand establishment. A research approach that tests stand establishment systems consisting of multiple factors was used. This trial tested the effect of four factors on emergence of seed of seven species surface planted in the fall of 2010: 1) Row cover was tested as a protective barrier against soil desiccation and bird damage, 2) Sawdust was tested as a substitute for the protective effect of organic debris, 3) Sand was tested to help hold the seed in place, 4) Seed treatment was evaluated for protection of emerging seed from fungal pathogens. The treatments did not test all possible combinations of factors, but tested the combinations that might work together to produce the best stand establishment. All treatment combinations also had rodent control, a drip tape irrigation system if necessary, and distractions for birds. By the first emergence count on March10, 2010, all species had started emerging. By April 9, row cover plus sawdust plus seed treatment had resulted in higher emergence than bare ground with sawdust plus seed treatment for Penstemon deustus, Heliomeris multiflora, Crepis intermedia, and Balsamorhiza sagittata. Emergence and stands were better for Penstemon deustus with row cover plus seed treatment than with row cover plus sawdust plus seed treatment. Including seed treatment to rowcover plus sawdust did not improve emergence of any species, with the possible exception of Dalea ornata, but actually reduced the stand of Penstemon deustus, Heliomeris multiflora, and Crepis intermedia on April 9. Adding sand to rowcover plus sawdust plus seed treatment significantly increased emergence only for Crepis intermedia on March 10. Averaged over species, row cover with sawdust resulted in the highest emergence. Row cover appeared to be the important factor in improving emergence.